My take on this, spurred by a discussion that went along the lines of
Cupboard: I think the Spirit wire cutters are crap
Magic Bus: I think the Spirit wire cutters aren't crap
Cupboard: (thinking maybe I'm just being mean to them) OK, I'll prove it.
The contestants: Gerber: Dime; Leatherman: Squirt PS4, Juice CS4, Skeletool, Wingman, Rebar head on Wave, Wave head on Rebar; Victorinox: Swisstool Spirit X
The challenges: 0.2mm^2 1000V stranded equipment wire, 0.5mm^2 tri-rated stranded equipment wire, 0.25mm^2 horrible nasty yuck 2 core bell wire that nothing will cut properly, 2.5mm^2 tri-rated stranded equipment wire, 2.5mm^2 stranded conduit cabling (thick strands), 6mm^2 tri-rated stranded equipment wire, 0.75mm^2 3-core flex.
The scoring: as above pretty much. I wasn't quite as thorough I guess. I have pictures of everything so ask if you want them. I have included the marginally less boring ones.
1. Cuts completely through with clean, smooth ends.
2. Cuts completely through with rough ends.
3. Cuts almost completely through to the point where a second snip would finish and be usable.
4. Doesn't cut through, requires another cut or maybe two, leaves it a mess.
5. Total failure, complete mangulation of the wire, no amount of retries will ever get it cut. You're better off chewing through it or banging it between two rocks.
Notes: I didn't always clear up the last MT's test pieces before taking the picture of the current one. If you see a picture of a load of clean cuts with a mangled bit at one side, that's the reason.
The results:
Gerber Dime:0.2mm^2: 3
0.5mm^2: 3
0.25mm^2 bell: 5
2.5mm^2 tri-rated: 5. It just twists the jaws
2.5mm^2 conduit: 5. As above
6mm^2: Cutters too small
0.75mm^2 3-core: Cutters too small
Squirt PS4:0.2mm^2: 1
0.5mm^2: 1-2
0.25mm^2 bell: 4
2.5mm^2 tri-rated: 1
2.5mm^2 conduit: 1
6mm^2: Cutters too small
0.75mm^2 3-core: Cutters too small
Juice CS4:0.2mm^2: 1
0.5mm^2: 1
0.25mm^2 bell: 4
2.5mm^2 tri-rated: 2
2.5mm^2 conduit: 1-2
6mm^2:
0.75mm^2 3-core:
Skeletool:0.2mm^2: 1
0.5mm^2: 1-2
0.25mm^2 bell: 3. Almost certainly because they aren't very worn.
2.5mm^2 tri-rated: 2
2.5mm^2 conduit: 2
6mm^2: Cutters too small
0.75mm^2 3-core: Cutters too small
Wingman:0.2mm^2: 1
0.5mm^2: 1
0.25mm^2 bell: 3: Given that the Wingman wire cutters were well renowned to be non brilliant and my decent bypass wire cutters at work struggle with this, the result is remarkably good.
2.5mm^2 tri-rated: 2
2.5mm^2 conduit:
6mm^2: 2, but more effort than others
0.75mm^2 3-core: 2. Very good considering it wasn't really big enough!
Rebar head on Wave:0.2mm^2: 1
0.5mm^2: 1
0.25mm^2 bell: 2-3, about as good as it gets.
2.5mm^2 tri-rated:
2.5mm^2 conduit: 1-2. It cuts cleanly but the lack of clearance on the back side of the cutters tends to apply some squishage.
6mm^2: 2
0.75mm^2 3-core: 1-2
Wave head on Rebar:0.2mm^2: 1
0.5mm^2: 1
0.25mm^2 bell: 3-4
2.5mm^2 tri-rated: 1
2.5mm^2 conduit: 1
6mm^2: 2
Was easier than the Rebar head, but tended to do this if you weren't careful:
0.75mm^2 3-core:
Spirit X:0.2mm^2: 3-4: really, this isn't hard to cut.
0.5mm^2: 3-4, as above
0.25mm^2 bell: 5, but then everything struggles with this. The only thing I can reliably cut it with in 1-2 goes is a pair of really good, really sharp side cutters.
2.5mm^2 tri-rated: 4. Pretty mangled but if you really kept at it you'd get there eventually.
2.5mm^2 conduit: 1-2: very good. The thick cores helped it.
6mm^2: Cutters too small
0.75mm^2 3-core: Cutters too small
The Squirt PS4 really surprised me actually. It was a very good cutter up until its jaws couldn't get round the fat stuff. The Wave cutters tended to go through more easily but the Rebar cutters cut with a more reassuring "snip". I think the Wingman is much maligned - it isn't all that bad.
Many thanks to Stephen (who I work for) for the bits of cable. Not that I've told him yet! They were all offcuts or second hand
Lastly: Al: all bar the Dime will happily grip an M10 nut, and that's the largest I can get my hands round the handles with. The Wave and Rebar both have similar placement in relation to the cutters due to the Rebar cutters being angled back.